How to draw 'inverted' line in a transparent form ?

[iPrank]

The attatched project uses snippet from Bushmobile's 'Glass Form' to create a transparent form. I want to draw lines in this form with inverted color. I tried DrawMode=Invert. But it didn't work in this case.
Any more idea ?

Currently I'm drawing black & white lines. But I want this:

[Milk]

I can think of a way you could do this but it requires a fair bit of messing.
As far as I understand if you want the inverted lines you will have to capture the DC of the desktop under the form and then blit the inverted desktop onto the form. Anything working with the DC of the form will just see the forms transparent colour.
If you subclass then I guess it would be possible to just do this at the right times, eg forms been moved or a form under the form has moved. Otherwise you would have to redraw constantly just in case the desktop changes or form moves.

More hassle than it's worth IMHO.

There might be other options but I don't know them.

[chemicalNova]

Have you tried setting the drawmode with an API? Then using MoveTo/LineTo ?

More specifically.. the SetROP2 API using R2_NOT, which draws it inverted.

chem

[iPrank]

@Milk:
Thanks for posting. I've already experimented your idea in another project. And yes, as you have said, it is a messy way and the result is not very good.

@Chem:
I didn't know about the API. Thanks. Let me see what happens...

[iPrank]

No. That didn't work.

I've modified this line in APIGuide code:

   Me.AutoRedraw = True
    'check the current mix mode
    If GetROP2(Me.hdc) <> R2_NOT Then
        'set the current foreground mix mode to R2_WHITE (Pixel is always 1)
        SetROP2 Me.hdc, R2_NOT
    End If
    'Draw a line from (0,0)-(200,200)
    LineTo Me.hdc, 200, 200

But it behaves same as DrawMode=Invert (The line becomes red).

[chemicalNova]

Have a look at MSDN.. more specifically here: http://msdn2.microsoft.com/en-us/lib...12(VS.85).aspx

There is a list of all the possible values for SetROP2. Try a few others until you get what you want.

chem